DESCRIPTION (Adapted from the application) The Immunoassay/ Radioligand core is a shared center facility whose aims are to1) develop new immunoassay's and new radioiodination and radioligand purification procedures; 2) Make available to center members a wide variety of radioimmunoassays, ELISAs, and receptor ligands; 3) Maintain rigorous quality control program for all radioimmunoassays, ELISAs, and receptor ligands provided by the core; and 4) to provide research oriented training in principles and methods of analyses of immunoassays and radioreceptor characterization methods.